I used Live One Care for a year on one laptop in the office and on my home machines (it was a 3 user subscription and I brought the laptop in from home for office use). It seemed ok. I'm not sure I ever trusted it completely. I would not trust it for a server. It did not slow things down that much however.
At the same time I used Live One Care I had Norton Antivirus in the office (the Server/multiuser edition). After some issues and lost data with AC, I switched to AVG network edition last year and have been very happy. My IT person is a reseller so I just had him come in and load it on the server and the other machines in the office, so I don't know how hard it might be to load on a server (they had to use a special program to get rid of all the tentacles of the Norton program). I did need to buy a retail version to get a few extra licenses and it loaded on the client machines without a hitch (just disable the firewall option on the client machines if you have the server version, since it gives no extra protection and will just slow things down). Good luck.
